A synchronizing technique used with data streams with periodically recurring bits and equal length bytes is to provide a fixed start of frame pattern and insert into certain of these bytes as required additional "stuffing" bits to prevent the payload from reproducing the synchronizing pattern. Disadvantages in the employment of that technique is that it introduces into the stream inequality of byte length and lack of periodicity in the rate of frame recurrence so as to possibly cause difficulties and adverse consequences downstream.
Another synchronizing technique is to generate at each of successive positions in the stream, separated by time intervals, a single localized synchronizing pattern constituted of the binary values of bits reserved for the pattern, the same pattern being produced at all such positions, and such pattern being distinctive and uncommon in character in relation to other bit patterns normally occurring in the stream. The disadvantage of such latter technique is that it fails to be wholly deterministic in its identification of information in the stream as being synchronizing information. That is so because, no matter how distinctive such synchronization pattern is, there is always, from the statistical viewpoint a finite probability that a sequence of bits in the stream including other than such reserved bits will generate a binary valued pattern not the true synchronization pattern but exactly duplicating it so as to be indistinguishable from it.